Jimh Posted May 5, 2009 Share Posted May 5, 2009 Just look at all those pins. What an abortion. Next time you have a camera any where near it can you take one of the gaiter on the brake cylinder please? Ours had disappeared and I'd like to see what I'm looking for. Quote Link to comment Share on other sites More sharing options...
gritineye Posted May 5, 2009 Share Posted May 5, 2009 Just look at all those pins. What an abortion. No offense Jimh, but I feel that I have to stick up for Oliver North here, he designed a rod and cable braking system in 1927, made it work on a bogey axle where any of the four wheels can be 2ft above the other diagonally, rotating in a 2ft radius around the axle center line, and where the wheels rise and fall in a vertical plane, with a diff casting in the way, and all this without any sign of the brakes dragging or applying unevenly. Gets my vote as a pretty good sort of bloke to have in a design team, no computers then either, pencil, paper and a good brain! This is a proven design that saw service from the first prototype right through till now, probably badly maintained in latter years too, nothing is wrong with it, if it wasn't so good some one would have started modifying them by now, any ideas how it could be improved would be of interest...................................:coffee: Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted May 5, 2009 Share Posted May 5, 2009 This is a proven design that saw service from the first prototype right through till now, probably badly maintained in latter years too, nothing is wrong with it, if it wasn't so good some one would have started modifying them by now, any ideas how it could be improved would be of interest...................................:coffee: Seeing as you asked, have a look at the simple but effective system used on the Martian which has a similar walking beam arrangement; my Martian cargo brakes were powerful enough to lock up all 4 rear wheels on a dry road with a 6 ton load in the back. Quote Link to comment Share on other sites More sharing options...
croc Posted May 5, 2009 Share Posted May 5, 2009 I have to agree with Bernard, nothing wrong with the brake system. As long as you take the time to grease it, it works very well, better than messing about with brake fluid and wheel cylinders. As with most things the best way to keep them working is to use them. Quote Link to comment Share on other sites More sharing options...
Stormin Posted May 5, 2009 Share Posted May 5, 2009 No offense Jimh, but I feel that I have to stick up for Oliver North here, he designed a rod and cable braking system in 1927, made it work on a bogey axle where any of the four wheels can be 2ft above the other diagonally, rotating in a 2ft radius around the axle center line, and where the wheels rise and fall in a vertical plane, with a diff casting in the way, and all this without any sign of the brakes dragging or applying unevenly. Gets my vote as a pretty good sort of bloke to have in a design team, no computers then either, pencil, paper and a good brain! This is a proven design that saw service from the first prototype right through till now, probably badly maintained in latter years too, nothing is wrong with it, if it wasn't so good some one would have started modifying them by now, any ideas how it could be improved would be of interest...................................:coffee: Where do the air actuators come in then? Surely if the air actuators where mounted on the walking beams it would've been simpler. No problem with lack of movement with flexible air lines. No problem with brake balance as pressure would be equal in all cylinders. Looking at the Scammell system there can't be more than too actuators on the rear brakes. If one of them fails or a link rod is damaged how much braking force is left. Particularly a problem on a pioneer I feel with no front brakes. All those link rods are prone to damage. Looking at Andys I can see one is severely bent. Quote Link to comment Share on other sites More sharing options...
croc Posted May 5, 2009 Share Posted May 5, 2009 There is only one actuator for the rear brakes, but even without it the brakes will work (to a point, but you really have to stand on the pedal) the one of Andys' that looks bent is actually a cable. The design of the linkages and compensators allows the pressure to be evenly distributed to each wheel. Quote Link to comment Share on other sites More sharing options...
gritineye Posted May 5, 2009 Share Posted May 5, 2009 (edited) Seeing as you asked, have a look at the simple but effective system used on the Martian which has a similar walking beam arrangement; my Martian cargo brakes were powerful enough to lock up all 4 rear wheels on a dry road with a 6 ton load in the back. Never looked at one of those Mike, any pix? Where do the air actuators come in then?Surely if the air actuators where mounted on the walking beams it would've been simpler. No problem with lack of movement with flexible air lines. No problem with brake balance as pressure would be equal in all cylinders. Looking at the Scammell system there can't be more than too actuators on the rear brakes. If one of them fails or a link rod is damaged how much braking force is left. Particularly a problem on a pioneer I feel with no front brakes. All those link rods are prone to damage. Looking at Andys I can see one is severely bent. I think air was a bit of a new thing in 1927, and buyers where a conservative lot then. The single air servo is up on the chassis, the bent rod you are looking at is a cable, the fulcrum that looks crooked is a compensator of which there are two, it moves to even out the pull. Never heard of anyone ripping any bits off (in peacetime at least!) PS. don't forget the beauty of the whole contraption, Scammell owners have a good eye for the perfect mechanical form! :-D Edited May 5, 2009 by gritineye left PC and croc beat me to it Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted May 5, 2009 Share Posted May 5, 2009 Where do the air actuators come in then?Surely if the air actuators where mounted on the walking beams it would've been simpler. No problem with lack of movement with flexible air lines. No problem with brake balance as pressure would be equal in all cylinders. Looking at the Scammell system there can't be more than too actuators on the rear brakes. If one of them fails or a link rod is damaged how much braking force is left. Particularly a problem on a pioneer I feel with no front brakes. All those link rods are prone to damage. Looking at Andys I can see one is severely bent. Pioneer/Explorer use a single air actuator which works the rear brakes through a system of mechanical compensators to give even braking across all 4 wheels. If the air system fails there is still a mechanical linkage back to the brake pedal. As you have suggested, using a single actuator per wheel is far simpler and is the system used on Martian, although still with single line and no handbrake for the wheels, just a large disc on the transfer rather like a Lend Raver. Quote Link to comment Share on other sites More sharing options...
gritineye Posted May 5, 2009 Share Posted May 5, 2009 Don't forget the beauty of the whole contraption, Scammell owners have a good eye for the perfect mechanical form! Those air actuators are so ugly! :-D Quote Link to comment Share on other sites More sharing options...
radiomike7 Posted May 5, 2009 Share Posted May 5, 2009 Never looked at one of those Mike, any pix? Sorry but no, you need to remove a rear wheel to get a good picture of how it works, but basically the Martian rear end is similar to the Watford version but heavier duty and with a conventional spiral bevel diff instead of a worm and wheel. Each wheel has a large drum with a vertical air actuator, all four actuators running from a common feed. It could have been even better if the actuators had a spring for parking, but the simple solution of spring secondary/park brakes was not thought of until the 60s and parking was catered for by a large disc on the transfer. Quote Link to comment Share on other sites More sharing options...
Jimh Posted May 5, 2009 Share Posted May 5, 2009 I once saw Oliver North at a book signing in a Walmart just outside San Diego. I think it was probably the Iran/Contra serial misunderstanding Oliver North rather than Scammell's designerbut I thought I'd mention it. Although I'm happy to be rude about a design that was past its best before date it is possibly alittle unfair on Scammell to comment on it without knowing what they had been made or encouraged to do by the people who were paying for the vehicle. Clients ask for daft things sometimes. Quote Link to comment Share on other sites More sharing options...
AndyFowler Posted May 5, 2009 Author Share Posted May 5, 2009 (edited) Hi Jim , Hope these help !:-D Edited August 12, 2009 by AndyFowler Quote Link to comment Share on other sites More sharing options...
thor698 Posted May 5, 2009 Share Posted May 5, 2009 good to see she is coming on:yay: Quote Link to comment Share on other sites More sharing options...
AndyFowler Posted May 5, 2009 Author Share Posted May 5, 2009 Thanks mate ! She'll be finished one day !:-D:-D:sweat::sweat: Quote Link to comment Share on other sites More sharing options...
thor698 Posted May 5, 2009 Share Posted May 5, 2009 she will be worth it:) Quote Link to comment Share on other sites More sharing options...
Jimh Posted May 5, 2009 Share Posted May 5, 2009 All that gunk seems to have preserved it very nicely. Quote Link to comment Share on other sites More sharing options...
julezee001 Posted May 5, 2009 Share Posted May 5, 2009 Sorry but no, you need to remove a rear wheel to get a good picture of how it works, but basically the Martian rear end is similar to the Watford version but heavier duty and with a conventional spiral bevel diff instead of a worm and wheel. Each wheel has a large drum with a vertical air actuator, all four actuators running from a common feed. It could have been even better if the actuators had a spring for parking, but the simple solution of spring secondary/park brakes was not thought of until the 60s and parking was catered for by a large disc on the transfer. I wish my Mk1 Militant had a set up like the Martian, with one cylinder per wheel on the rear instead of one for both axles each side, it would give her better brakes, make her far easier to adjust, and get through a brake test! She probably has a better handbrake with the ratchet on type working all 4 rear brakes, similar to the Scammells. Jules Quote Link to comment Share on other sites More sharing options...
daz76 Posted May 6, 2009 Share Posted May 6, 2009 Terrific photos Andy! You're really cracking on with Daisy now. You'll be back on the road in no time. A real inspiration to get back to my restoration this summer. Not going to be pretty after winter under a tarp but I just wish there were either more hours in a day or more days a year! good luck continuing the great job. Quote Link to comment Share on other sites More sharing options...
AndyFowler Posted May 7, 2009 Author Share Posted May 7, 2009 Thanks Daz ! Thats one of the great things about this forum that we can all inspire and motivate one another just by a few pictures and kind words and gentle persuasion in the right direction ! :-D Quote Link to comment Share on other sites More sharing options...
gritineye Posted July 28, 2009 Share Posted July 28, 2009 Sorry Andy but it has to be shown, your public is hungry for it! :-D Something went wrong... Hope you enjoyed the drive, see ya next time.........:sweat: Quote Link to comment Share on other sites More sharing options...
Chrisg Posted July 28, 2009 Share Posted July 28, 2009 :tup:: Thanks Bernard Quote Link to comment Share on other sites More sharing options...
AndyFowler Posted July 28, 2009 Author Share Posted July 28, 2009 Words cannot express how sorry I am to have damaged your NEW headlamps mate ! Hope this shows how sorry :cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry::cry: :iloveyou: Quote Link to comment Share on other sites More sharing options...
gritineye Posted July 28, 2009 Share Posted July 28, 2009 Errrmmm...........it's a start........not sure about the :iloveyou:....:shocked:...Forceful is a MAN'S truck you know. Quote Link to comment Share on other sites More sharing options...
AndyFowler Posted July 28, 2009 Author Share Posted July 28, 2009 Errrmmm...........it's a start........not sure about the :iloveyou:....:shocked:...Forceful is a MAN'S truck you know. I must have been heavily influenced by the Peace part of the show mate ! :-D Quote Link to comment Share on other sites More sharing options...
gritineye Posted July 28, 2009 Share Posted July 28, 2009 well we know about the flower power bit. :-D Quote Link to comment Share on other sites More sharing options...
.thumb.JPG.b2adad6b4fc61f6f441afb521e654559.JPG)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.